Is there an "absolute hot"?

Question

We know that temperature is another word for particle movement. The lowest possible temperature, known as "absolute zero", −273,15° Celsius or 0 K, is the point where the particles don't have any kintec energy, thus not moving.

So what is the highest possible temperature? My assumption is that particles cannot move faster than light (or, any particle with mass actually cannot reach c), so is this point the highest possible temperature?

Thanks in advance and I apologize for any language mistakes (I live in Germany)

You can google negative temperatures, Hagedorn temperature and Planck temperature. — jinawee, Feb 03 '20 at 15:58
Does this answer your question? Why is there no absolute maximum temperature? — jacob1729, Feb 03 '20 at 15:59
I suspect that at some temperature the energy is so large that the "object" becomes a black hole. — , Feb 03 '20 at 16:57

score 2 · Accepted Answer · answered Feb 03 '20 at 16:09

In at least one sense, yes: -0K

https://en.m.wikipedia.org/wiki/Negative_temperature

This happens where you have a system with a limited number of discrete energy states. At +0K, everything is in the lowest possible energy state; at ±∞K, all energy states are equally occupied; and at -0K, everything is in the highest energy state possible.

This only happens in bounded systems, because the ±∞K temperature has maximum entropy and getting hotter from that point onwards reduces the entropy. In an unbounded system, making something hotter always increases entropy, so the temperature never wraps around.

Separately, there is also the Plank temperature:

https://en.m.wikipedia.org/wiki/Planck_temperature

This is the point at which the blackbody spectrum reaches the Plank length, which might or might not be a real limit, but is definitely where our current understanding fails.

score 1 · Answer 2 · answered Feb 03 '20 at 16:10

First of all, temperature of any body doesn't mean that the atoms in the body are moving or are kinetic. But they oscillate, when the temperature increases the oscillation increase.

Now coming to the question of limit. There is absolutely no limit of how hotter the temperature can increase.

Sun has a temperature of 15 million Kelvin. So at this temperature things are not solid, liquid or gas. They are in state of plasma. Due to this high temperature the electrons wander away from the nucleus. But again this is not the limit. Infact when a much bigger star collapses, at the last day of its collapse (when it shrinks) the temperature reaches 3 Billion Kelvin. Again not the limit but surely a limit to something which is about protons and neutrons inside the nucleus.

At 1 TERA Kelvin (1000000000000 kelvin) electrons not only wander away but the protons and neutrons MELTS. Eg. Of this temperature is when a star WR104 (mass about 25 suns) collapses it will release energy is greater than the energy sun has ever produced in its entire life.

Is there an "absolute hot"?

2 Answers2